More Americans are spending less time with members of the households, according to the results of a study released this week.

The University of Southern California’s Center for the Digital Future found that 28 percent of Americans it interviewed last year said they have been spending less time with members of their households. In 2006, 11 percent of Americans had said the same.

Furthermore, significant percentages of Internet users said they were sometimes or often ignored because another member of the household spends too much time online (44 percent). An even higher percentage (48 percent) said they were ignored because others spend too much time watching TV.

“The primary purpose of the studies conducted by the Center for the Digital Future is exploring the profound changes in views and behavior that have occurred during those 15 years of Internet use – as well as the changes yet to come,” reported Jeffrey I. Cole, director of the Center for the Digital Future at the USC Annenberg School for Communication.

Since 2000, the center’s Digital Future Project has examined the behavior and views of a national sample of Internet users and non-users, as well as comparisons between light users (5 hours or less per week using the Internet) and heavy users (more than 24 hours per week on the Internet).

The publication of Year Eight of the Digital Future studies comes at a milestone moment in the evolution of the Internet; 2009 marks 15 years since Web sites became generally available to the American public.

Among their findings, the Center for the Digital Future revealed a growing concern for families in America, though a growing percentage of Internet users said the Internet is important in helping to maintain social relationships.

According to the study, the percentage of adults who said that the children in their households spend too much time using the Internet has increased for the fourth year in a row. In the current study, 28 percent of respondents said this, marking another new high for the Digital Future Project.

Overall, the amount of time that Internet users spent online has grown in each year of the Digital Future studies, and has now surpassed an average of 17 hours per week.

Other findings in the 2009 Digital Future Project include those pertaining to online newspaper readership, what internet users are doing online, online communities, and the political power and influence of the internet.

Today, the percentage of Americans who use the Internet has reached 80 percent, according to the current Digital Future study.

The highest percentage of Internet use is among Americans under age 18.